In installing carpet, it is necessary to stretch the carpet across the floor in order for the installed carpet to lie flat and taut. Carpet installers often use gripping tools, such as knee kickers and other similar devices, in order to grip the carpet and stretch or move it into position. These devices use a gripping block having a multiple number of “nap teeth” which are closely-spaced together. The nap teeth are typically made of spring steel wire which grasps the loops of the carpet fibers to pull the carpet along. The gripping block is mounted in a carpet gripping tool to grasp the carpet as the carpet is manipulated into position with the tool. The problem with nap teeth is that fibers will pull out of the carpet and accumulate in the closely-spaced nap teeth thereby further reducing the gripping ability or “nap grip” of the block. Conventional nap teeth are also generally less effective in gripping “sheared” or “cut pile” carpet.
To grip these types of carpets, carpet tools also use heavy retractable pins in combination with the nap teeth. The pins can extend downward past the nap teeth to pierce the backing of the carpet, increasing the effective gripping power of the tool. The problem with these pins is that they can extend further through the carpet backing and tear the underlay as the carpet is stretched into position. Some carpets have water-blocking membranes as part of the backing. The use of knee kickers with retractable pins on these types of carpets can tear the membrane thereby destroying the water-blocking capability of the carpet.
It is, therefore, desirable to have a gripping block for use with carpet gripping devices that grasp the carpet without piercing through the carpet backing and tearing the underlay or membrane positioned underneath the carpet as it is stretched into position.